..However, the segmental origins of their brain neuropils and the number of cephalic appendages innervated by the brain--key issues in clarifying brain composition in the last common ancestor of Onychophora and Arthropoda--remain unclear...

Neural development in Onychophora (velvet worms) suggests a step-wise evolution of segmentation in the nervous system of Panarthropoda

..Our data best support the hypothesis that the ancestral panarthropod had only a partially segmented nervous system, which evolved progressively into the segmental chain of ganglia seen in extant tardigrades and arthropods...

..Our findings, thus provide, to our knowledge, first morphological/embryological support for the monophyly of the Paradoxopoda and suggest that the mandible might have evolved twice within the arthropods...

Distribution of serotonin in the trunk of Metaperipatus blainvillei (Onychophora, Peripatopsidae): implications for the evolution of the nervous system in Arthropoda

..Furthermore, the model predicts segment deletions when there is an interruption in cell division, just as seen in heat shock experiments, as well as the growth and final shrinkage of the presomitic mesoderm during somitogenesis...

The mitochondrial genome of the onychophoran Opisthopatus cinctipes (Peripatopsidae) reflects the ancestral mitochondrial gene arrangement of Panarthropoda and Ecdysozoa

..rowelli revealed no cumulus-like accumulation of dpp expressing cells at any developmental stage, suggesting that this feature is either a derived feature of chelicerates or a synapomorphy uniting the chelicerates and myriapods. ..

Myoanatomy of Myzostoma cirriferum (Annelida, Myzostomida): implications for the evolution of the myzostomid body plan

..cinctipes. From this survey, no evidence in support of a "long germ band" hypothesis in Opisthopatus was found. Instead, the embryogenesis in representatives of Opisthopatus is more similar to that in other onychophorans than expected...